spudpeel

Revising for Biology exam tomorrow, im so convinced that the formats have changed in all edexcel exams and everythings gone terribly difficult.... Surely I'm not the only one in the country? Maths was evil, Chemistry was evil, god knows what biologys going to be like tomorrow...gd luck all..

Nope dint drink it! Basically the hope was that the thermite would drip onto the KNO3 and gin in the can beneath and make a nice fire, it didnt though, it just boiled so we added more stuff. In the end the fire had gone out, though it was really hot and was bubbling quite strongly by itself. Holding a daisy to it made the petals go green. I think I should stop getting distracted from revision..

I was mucking around with chemicals at the weekend, and we mixed anything vaguely flammable together (stupid i know).. As far as i know, our cocktail included: Rust, Aluminium, gin, KNO3, Sulphur and Magnesium. Oh, and burnt matches. Can anyone shed any light on why it loads of ammonia was evolved?! I know that the test for nitrates uses aluminium and generates ammonia, but this requires NaOH, which i didn't add. My only other thought is that KOH from the burnt matches did it instead, but i dont know if this is possible.. Any ideas?

I have been told that there are 2 strands of DNA in the helix because the complementary strand prevents mutation to the structure and makes it more stable. this makes sense, but my problem is that this suggests that only one strand codes for anything. My teachers said the DNA is read from the 5' end to the 3' end (or vice versa?), and so it cannot read the DNA on the other side, but surely, if the whole molecule is turned through 180 degrees, the complementary bases can be read? And if not, is there a marker which signifies the strand to be read? They also said that DNA can only be read from a promoter sequence, but surely these can exist in the other strand? I'd really appreiciate it if someone could answer this. It's probably badly written, so i hope you know what i mean!

My intrigue into Uv stuff took me to ebay to find a cheap UV tube.... I found a bid for 40!!! 9" Uv tubes, and i managed to get them for, wait for it.......... £7.50!! Theyr working lovely, I just made tonic water blue and a few mins ago found out that they cost £10 each.. Just thought id share my happiness with the world!

I wasn't going to use pure quinine, i did mean just using tonic water. Im sure the website i looked on said Vit B12, and it said that it would glow bright yellow. It could easily have been B2, which if you've never seen before is ridiculously yellow! My work experience was at a vitamin mixing factory, and i came home caked in the stuff!

Naphthalene, the smell of moth balls.... that has to be one of my favourites, anything oily - unburnt diesel, engineering oil, etc.

I've looked into how glow sticks work, but wonder if there would be any way to make edible ones using foodstuffs?.. I know that quinine is fluorescent, and apparently so is Vit-B12 and chlorophyll, but are there any other chemicals i could use to make them? Also, are there any chemiluminescent reactions that could be used?

Which reactions are you trying to study? The only technique for learning i can think of at the moment is how i remember the conditions for producing grignard reagents.. GRIME : Grignard, Reflux, Iodine, Magnesium, Ether

I was watching the RI xmas lectures yesterday ( ), and it said that heavy nitrogen isotopes accumulate in animals, wheres this does not happen so much in plants. Since nitrogen isotopes behave the same chemically, and any nitrogen would have come from a primary consumer anyway, how is this possible?

Im doing psychology and at the moment we're studying education. There are loads of studies on Race, gender and other differences in people which seem to be related to IQ. As much as I hate terminology, IQ tests can be ethnocentric, i.e. suited to certain cultures. Language to understanding the questions can also be a barrier to success. Somebody (i dont know who) showed black children fostered by white parents have comparable IQ to white children fostered by white parents. This suggests that intelligence is possibly not inherited.

Sunspot: I follow all of that, and it all seems to make sense, but is there any hard evidence for it? I am always told that I can't say things like that without evidence and that I cannot generalise to other situations.

In our area theres every opportunity to recycle, so we do lots. We had to give up composting veg waste etc 'cos it stinks the kitchen and garden out.

The laws are weird in the UK for prostitution, you can go to them, but they can't go to you (lurking around in public that is).

I am currently studying educational psychology, and have just covered a study by Mellanby et al. which suggests that the reason for girls exceeding boys academically is due to the curricula and the schooling being more suited to girls. What exactly is meant by this, and how is it possible to actually scientifically prove this?

Wow, if only I'd known that then, (3 years ago), I wouldnt have had to go to the DT department to get sandpaper to remove it...

I think some of Freud's stuff is great, what i have read about boys trying to internalise a male role model, and thus rejecting the female teachers' behaviours and values in schools is great, although it is clearly not scientific and entirely untestable. Some of it does seem to follow though.

I got in big trouble with a certain teacher for questionning this once! Im a moles man myself, and 2% glucose solution completely confused me. I got into a big argument because of it.

Its easy to get hold of, I use it with glycerine for lighting barbeques spontaneously without matches because im weird like that. But don't get it on your skin cos it stains them a lovely brown colour that you cant remove.

Excellent, thanks woelen, that's put my mind at rest. Acids are strong if they dissociate readily to give H+ ions, and bases are strong if they readily accept the H+ ions.

I've asked my chem teacher this before, but still don't quite get it. In titration curves, e.g:http://www.chemguide.co.uk/physical/acidbaseeqia/summary.gif Why is there a sudden drop or rise in pH towards the equivalence point, is it due to the logarithmic nature of the pH scale, or am I missing something?

To me, the best chemical smell by far is naphthalene!

Fair enough, thanks for your help anyways

I meant SDI to be species diversity index, we use Simpson's reciprocal index at A2. I think the values are scale data, since i can plot a graph of them?

Hypothesis: There is a relationship between the depth of soil on a pingo on foulden common and the species diversity supported by it. (A pingo is a small hill) The profile of the pingo was divided into 8 height zones, the occurences of each species recorded at each one of them, and then sdi values calculated. 9 soil samples were taken to estimate the mean water content of the soil at each height zone.